Some prior art constructions of rotors for vertical hydro-generators permit detachment of the rim with pole-pieces from the frame of the rotor as the hydro-generator is assembled or disassembled in the well of the hydraulic plant. It arises from the tendency to place less stringent requirements on the load-carrying capacity of the assembly equipment. This disconnection feature is provided by a removable support means for supporting the pole-carrying rim after the rotor of the hydro-generator has been completely assembled. In one such rotor of a vertical hydro-generator /cf.Inventor's Certificate of the U.S.S.R. No. 429490/, comprising a shaft and a frame with wedge strips attached thereto, the strips have provided in their lower portion a horizontal transverse slot wherein a support means is disposed for supporting a rim with poles. The support means is formed by a member with a pair of longitudinal projections essentially of a channel section with one of its legs shortened, and interlocked with the lower portion of the wedge strip as a result of the upper shortened projection of the member engaging said slot provided on the inside of the wedge strip. In this case the end of the wedge strip is enclosed, from the bottom, by the lower elongated projection extending slightly beyond the outside surface of the strip to provide a support for the rotor rim.
One disadvantage of this construction consists in the fact that the bending stresses borne by the elongated support projection due to the mass of the pole-carrying rim may be significant, since the distance between the point of application of forces exerted by the mass of the rim and the point of attachment of the support means to the wedge strip is comparatively large. This is liable to result in deformation of the supporting projection and consequently in the axial displacement of the motor rim.
Another drawback of the construction is a difficulty encountered in fabrication of the support means: in order to provide satisfactory assembling of the device, it is necessary that the mating parts be shaped to conform to each other, in particular, at least the horizontal slot formed in the wedge strip should be shaped exactly to match the upper projection of the support means inserted into the slot. Moreover, in order that the horizontal slot be cut on the inside of all the wedge strips, the frame of the rotor has to be turned through 180 degrees, in the vertical plane with respect to its working position, so as to permit ready access for the cutting tool to the portion of the frame to be machined. Another disadvantageous feature is an increased amount of the material expended for providing larger dimensions of the lower portion of the wedge strip on the inside thereof, which is required for mounting and securing the support means at the point.
It also will be noted that when disassembling the rotor, the support means for supporting the pole-carrying rim sometimes has to be detached from the wedge strip of the frame, approaching from the side of the hydro-generator brake plate, which may be inconvenient.